444 AnacaediaoeuE. 



THE WAFEK-ASHES. Genus PTELEA L. 



Small trees or shrubs without prirkles aud with bitter bark. Five or six sijecies are 

 known, all nnti\es of the United Stales and Mexico, one only being arborescent and that 

 widely distributed throughout central aud eastern United States. 



Lrai-rs usually 3-toliate, long petiolate and without stipules: leaflets conduplicate in the 

 bud, ovate or oblong, entire or serrate, pellucid-punctate. Floivers greenish-white, polygamous, 

 in compound terminal cymes; calj'x with sepals 4-."i or wanting: petals 4-5, imbricated; 

 stamens of same number and alternate with them with subulate filaments, pilose at base 

 and shorter in the pistillate flowers; pistil superior, stipitate, with compressed, 2-.3-cellect 

 ovary, short style and 2-3-lobed stigma. Fruit an indehiscent 2-.j-celled samara, surrounded 

 by a broad reticulate wing (or rarely wingless) : seed pointed at apex, rounded at base and 

 with coriaceous testa. 



The name is the ancient Greek name of the Elm, given to this genus on account of a 

 resemblance in the fruit. 



For .tprcies see pp. 300-301. 



aUASSIA FAMILY. SMARUBACE^ DC. 



Trees, shrubs and a few herbs with generally bitter milky juice and confined mostly to 



tropical regions. About one hundred) forty-five species, grouped in twenty-eight genera, are 



known. Of these one arborescent genus (iSiinaruba) is indigenous to the United States in 



subtropical Florida. Another (Ailantliii.s) is extensively naturalized throughout eastern 



United States and Canada. 



Leaves' generally alternate and pinnate, not glandular-punctate, without stipules. 

 Ftoico-.v mostly in axillary racemes or panicles and dioecious or polygamous, regular: calyx 

 3-.5-lobed or parted, imbricated in the bud; petals 3-5 (rarely wanting), hypogenous : disk 

 annular or elongated: stamens as many as the petals or twice as many, with distinct filaments 

 each with a scale or hairs at base and inserted under the disk : anthers 2-celled introrse ; 

 pistils composed of 2-5 united carpels each of a single cell and containing a single anatropous 

 ovule ; style 3 -.5. Fruit a drupe or samara. 



THE AILANTHUS. Genus AILANTHUS Desf. 



Large handspme trees with jjale bark and of two or three species, natives of China, the 

 East Indies and Australia and rejjresented in the United States by a single naturalized species. 



Leaves simple, altrenate, deciduous, odd-pinnate, with numerous somewhat oblique sub- 

 entire leaflets. Flowers small, in large terminal panicles; cal.vx with 5 short lobes: petals 5, 

 valvate, spreading: disk hemispheric, 10-lobed ; stamens 10 (only 2 or 3 in the pistillate 

 flowers) : ovary deeply 2-5-lobed ; styles 2-5, united. Fruit sameras usually 2-5 together, 

 linear-obloug, with membranous veiny wing and cell containing a solitary compressecl seed 

 at about its center. 



The name is from the native Mallaca name of the tree — Ailauto, meaning Tree of liearen. 



For species see pp. 30.i-30.3. 

 SUMACH FAMILY. AXACARDIACEvE Lindl. 



Trees and shrubs with resinous or milky juice, of about fifty genera and four hundred 



species mainly of warm or tropical regions. Three genera are represented in the trees of the 



United States, 



Lcares mostly alternate and without stipules: branchlets terete and with large pith. 

 Flouers small, regular, polygamous, dioecious or perfect; calyx lobes mostly ?> ; petals of same 

 number and imbricated in the bud or none; stan)ens as many as the petals or twice as many 

 (rarely fewer) and inserted with them on the edge of an annular hypogenous disk: filaments 

 filiform and anthers oblong, introrse, 2-celled, longitudinally dehiscent : ovar.v usually 1-celled 

 and containing a solitary anatropous ovule suspended by a slender funicle rising from the 

 base of the ovary; styles 1-3, stigmas terminal. Fruit generally a small drupe; seed with 

 membranous or crustaceous coat ; cotyledons fleshy and containing little or no albumen. 



KEY TO THE GENERA. 



Styles lateral: fruit compressed with many abortive plumose pedicels; leaves simple. 



Cotlnus. 

 Styles terminal; fruit syn-.metrical ; leaves compoiuid (simple in some western species). 



Rhus. 



